Containers for beverages such as milk, cream, other dairy products, juices, and the like are conventionally constructed from thermoplastic coated paperboard. One type of these containers includes a top end closure with a folded gable roof having a vertically projecting seal at the roof ridge for sealing the container and providing a readily available pouring spout when the contents of the container are to be dispensed.
Thermoplastic coated paperboard blanks for constructing such a container are made on converting machines similar to those disclosed by Monroe et al. U.S. Pat. No. 2,682,208 and Earp U.S. Pat. No. 3,731,600. After construction, the blanks are processed by forming, filling and sealing machines, such as those disclosed by Monroe et al. U.S. Pat. No. 3,303,761, Allen U.S. Pat. No. 3,918,236, Egleston U.S. Pat. No. 3,398,659 or Young U.S. Pat. No. 4,193,833, to produce the formed, filled and sealed containers of the type referred to above and shown and described in Egleston et al. U.S. Pat. Nos. 3,270,940 and 3,120,335.
Typically, as shown and described in the forming, filling and sealing machines of the above referenced U.S. Pat. Nos. 3,303,761; 3,918,236 and 3,398,659, there are heating stations included on the machines to heat the various thermoplastic coated surfaces so that they can then be sealed together under pressure. Alternatively, as disclosed in the U.S. Pat. No. 4,193,833, sealing may be accomplished by ultrasonic or high frequency vibration.
For particular applications, a so-called thermoplastic "hot melt" may be applied as a sealant for various panel surfaces, or to serve as a sealant for crevices that may occur between the adjacent edges of co-planar panels after closing.
In still other prior art liquid carrying container arrangements, such as that shown and described in Wyberg U.S. Pat. Nos. 4,813,548 and 4,756,426, a fillet comprising a thin strip of stiff material coated with or adjacent to a layer of adhesive, which may be a type of pressure sensitive adhesive approved for food contact, is attached to the gable rib panels which form the spout. These arrangements contemplate the application of the usual heat sealing process to establish a conventional thermoplastic-to-thermoplastic bond.